Implicit Motion Vector Predictor Precision for Video Decoding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in indicating motion vector predictor precision, leading to suboptimal compression ratios and increased data requirements.
Innovation Solution
The method involves implicitly indicating motion vector predictor precision through predefined rules or high-level syntax, allowing for differential precision between motion vector predictor and difference, enhancing the decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vector predictor precision is explicitly indicated for every motion vector, then prediction accuracy is improved, but bitstream data requirements increase
Solution Approach 1:
The patent applies local quality by differentiating precision requirements between motion vector predictors and motion vector differences. The motion vector predictor uses higher precision (e.g., 0.25 pixel) while the difference uses lower precision (e.g., 0.5 pixel), optimizing the balance between prediction accuracy and data efficiency. This is achieved through implicit precision indication where the decoder infers different precision levels from the syntax structure itself.
Solution Approach 2:
The patent changes the precision parameter dynamically based on the relationship between motion vector predictor and difference. By using implicit precision indication through pre-defined rules and syntax structures, the system adjusts the effective precision of motion vector components without requiring explicit precision signaling in the bitstream, thus reducing data requirements while maintaining accuracy.
2Productivity
If higher precision is used for motion vector prediction, then compression performance improves, but decoding complexity increases
Solution Approach 1:
The syntax structure itself provides the precision information through implicit indication, eliminating the need for separate precision signaling bits. The decoder automatically determines the appropriate precision level by interpreting the syntax structure according to pre-defined rules, making the system self-sufficient and reducing both encoding and decoding complexity.
Solution Approach 2:
The precision rules are pre-defined before decoding occurs. The decoder uses these pre-established rules to automatically determine motion vector predictor precision without requiring real-time analysis or complex decision-making processes, thereby simplifying the decoding operation while maintaining high compression performance.
3Quantity of substance
If motion vector difference precision is reduced, then data requirements decrease, but prediction accuracy may be compromised
Solution Approach 1:
The patent applies partial action by providing higher precision only where necessary - specifically for the motion vector predictor component - while using lower precision for the difference component. This selective precision allocation optimizes the trade-off between data efficiency and prediction accuracy, as the predictor's higher precision compensates for the difference's lower precision in the overall motion vector calculation.
Data Source
AI summary
This disclosure relates generally to video coding/decoding and particularly for implicitly indicating motion vector predictor precision. One method includes receiving a coded video bitstream; determining, based on the coded video bitstream, a current block of a current frame to be inter predicted by at least one reference block of at least one reference frame; determining, based on the coded video bitstream, a motion vector (MV) of the current block to be predicted by a motion vector predictor (MVP) and a corresponding motion vector difference (MVD); determining an MVP precision according to an implicit indication, a pre-defined rule, or a high-level syntax, wherein an MVD precision associated with the corresponding MVD is different from the MVP precision; and reconstructing, by the device, the current block based at least on the MVP at the determined MVP precision and the MVD at the MVD precision that is different from the MVP precision.